Method and apparatus for treating film coated on substrate

Abstract

A film treating method treats a resist film which is formed on a substrate by spin coating. The method comprises a step for coating resist on the substrate to form the resist film, a step for conveying the substrate to a region having an atmosphere of a saturated vapor or a super-saturated vapor of solvent before the solvent contained in the resist film is lost, a step for executing a first heating process wherein the substrate is heated at a temperature which lowers the viscosity of the resist film and permits solvent to remain in the resist film in an amount sufficient to maintain the fluidity of the resist film, a step for conveying the substrate away from the region having the atmosphere of the saturated vapor or the super-saturated vapor of solvent, and a step for executing a second heating process wherein the substrate is heated at a temperature higher than that of the first heating process, thereby permitting the solvent to evaporate from the resist film.

What is claimed is: 
     
       1. A film treating method for treating a resist film which is formed on a substrate by spin coating, comprising: a step of coating a resist composition containing a solvent on the substrate to form the resist film;   a step of mounting the substrate coated with the resist film on a mount table;   a step of covering the substrate coated with the resist film with a cover so as to define a sealed small-volume space, whereby an atmosphere of a saturated vapor or a super-saturated vapor of the solvent is formed in said sealed small-volume space before solvent included in the resist film is lost;   a step of executing a first heating process in said sealed space wherein the substrate coated with the resist film is heated at a temperature which lowers the viscosity of the resist film and permits solvent to remain in the resist film in an amount sufficient to maintain the fluidity of the resist film;   a step of removing the cover so as to change said sealed small-volume space to a non-sealed space surrounding the substrate coated with the resist film; and   a step of executing a second heating process in said non-sealed space wherein the substrate coated with the resist film is heated at a temperature higher than that of the first heating process, thereby permitting the solvent to evaporate from the resist film.   
     
     
       2. A film treating method according to claim 1, wherein the substrate and the cover are kept away from each other by a distance of 10 mm or less when the substrate is overlaid with the cover. 
     
     
       3. A film treating method according to claim 1, wherein, in said first heating process, solvent vapor is supplied to the sealed small-volume space surrounding the substrate coated with the resist film, whereby the solvent of the resist film is prevented from evaporating when the substrate is heated. 
     
     
       4. A film treating method according to claim 1, wherein, in said first heating process, the substrate coated with the resist film is placed on the mount table with the mount table including heater means and means for controlling said heater means. 
     
     
       5. A film treating method according to claim 1, wherein said first heating process is executed before the resist film dries. 
     
     
       6. A film treating method according to claim 1, wherein said substrate coated with the resist film is heated at a temperature between 30° C. and 60° C. in the first heating process. 
     
     
       7. A film treating method according to claim 1, wherein said substrate coated with the resist film is heated for 20 seconds or longer in said first heating process. 
     
     
       8. A film treating method according to claim 1, wherein said substrate coated with the resist film is heated for 40 to 100 seconds in the first heating process. 
     
     
       9. A film treating method according to claim 1, wherein, in said first heating process, the substrate coated with the resist film is heated such that peripheral portions of the substrate coated with the resist film have a higher temperature than that of central portions thereof. 
     
     
       10. A film treating method according to claim 1, wherein, in said second heating process, the substrate coated with the resist film is heated at a temperature between 80° C. to 100° C. in a gas exhausting environment. 
     
     
       11. A film treating method according to claim 1, wherein, in said second heating process, the substrate coated with the resist film is heated at a temperature between 60° C. to 120° C. in a gas exhausting environment. 
     
     
       12. A film treating method according to claim 1, wherein said first and second heating processes are executed in first and second containers, respectively, and said second heating process is executed, with a gas in the second container being exhausted. 
     
     
       13. A film treating method according to claim 1, wherein said first and second heating processes are executed in a single container, said first heating process being executed with said single container being sealed, and said second heating process being executed with a gas in said single container being exhausted.